Patent application title: Method and apparatus for tissue fastening

Abstract:

Methods and apparatus directed to tissue capture, presentation and
retention using a surgical apparatus. One or more tissue capture arms can
include surface features that engage captured tissue and provide
omni-directional support during capture and retention of the tissue. The
tissue clamping arm can include improved centering features for
positioning captured tissue relative to a penetrator that is advance into
the capture tissue. Through improved tissue handling and tissue retention
relative to the penetrator, captured tissue can be consistently pierced
regardless of external forces and techniques. The tissue clamping arm can
include gripping members arranged along an interface surface to improve
tissue grip and presentation.

Claims:

1. A surgical apparatus comprising:a body assembly including a penetrator
assembly having a penetrator movable along a penetrator pathway; anda
tissue interface portion, the tissue interface portion having a insertion
head and a at least one tissue capture arm, each capture arm having a
convex capture lobe for interfacing with a concave positioning guide on
the insertion head and wherein each convex capture lobe includes a
plurality of gripping members arranged along a lobe interface surface of
the convex capture lobe in a first direction generally parallel to and
along the penetrator path and in a second direction generally transverse
to the first direction, wherein an arrangement of the plurality of
gripping members in the second direction defines an arcuate gripping
radius,such that a tissue drape formed of tissue captured between the
convex capture lobe and the concave positioning guide has a tissue drape
arc that generally conforms to the arcuate gripping radius and the
arcuate gripping radius defines a substantially constant insertion depth
of tissue relative to a surface of the penetrator along at least a
portion of the penetrator pathway.

2. The surgical apparatus of claim 1, wherein the constant insertion depth
is between about 0.005 inches to about 0.021 inches.

3. The surgical apparatus of claim 1, wherein the plurality of gripping
members define a capture surface including a plurality of raised edges
and a plurality of channels for gripping a surface of tissue.

4. The surgical apparatus of claim 3, wherein the gripping members can
comprise a raised castle configuration, a raised cube or combinations
thereof.

5. The surgical apparatus of claim 1, wherein an uppermost gripping member
and a lowermost gripping member on the lobe interface surface relative to
the second direction define endpoints of the tissue drape arc such that
the tissue drape arc extends between about 60.degree. to about
120.degree..

7. The surgical apparatus of claim 1, wherein the convex capture lobe
further includes a lobe leading surface and a lobe trailing surface, with
a clearance space defined between the lobe interface surface and the
concave positioning guide that exceeds a leading clearance space defined
between the lobe leading surface and the concave positioning guide and a
trailing clearance space defined between the lobe trailing surface and
the concave positioning guide, wherein tissue captured between the
insertion head and the at least one capture arm is squeezed out of the
leading clearance space and the trailing clearance space and into the
clearances space creating tension in the captured tissue leading to
formation of the tissue drape along the lobe interface surface.

8. A method for penetrating soft tissue other than bone in a patient,
comprising:providing a surgical apparatus having a penetrator movable
along a penetrator pathway in a first direction, the surgical apparatus
including a capture arm and an insertion head;grasping tissue between the
capture arm and the insertion head to form a tissue drape;forming a
tissue drape arc along an interior surface of the capture arm in a second
direction generally transverse to the first direction, the interior
surface including an arrangement of a plurality of gripping members that
defines an arcuate gripping radius in the second direction; andadvancing
the penetrator through the tissue drape arc in the first direction such
that the penetrator cuts through the tissue drape arc at a substantially
constant insertion depth relative to a surface of the penetrator along at
least a portion of the penetrator pathway.

9. The method of claim 8, further comprising:carrying a fastener with the
penetrator such that the fastener can be positioned within the tissue as
the substantially constant insertion depth.

10. A method for isolating external forces during creation of a
penetration in soft tissue other than bone in a patient,
comprising:providing a surgical apparatus having at least one capture arm
and an insertion head adapted to capture tissue therebetween, the at
least one capture arm including a plurality of tissue gripping members
defined along an interface surface of the capture arm and the insertion
head including a penetrator;grasping tissue between the capture arm and
the insertion head to form a tissue drape such that horizontal slippage
of the tissue drape is controlled by grasping an external surface of the
tissue drape with the tissue gripping members; andpresenting a generally
constant insertion depth of the tissue drape to the penetrator by forming
a tissue drape arc conforming to a gripping radius defined by the
plurality of tissue gripping members.

11. The method of claim 10 further comprising:advancing the penetrator
through the tissue drape arc to create the penetration in soft tissue.

12. The method of claim 11, further comprising:placing a surgical fastener
in at least a portion of the penetration in soft tissue.

13. The method of claim 10, wherein grasping tissue comprises:squeezing
tissue out of a leading clearance space and a trailing clearance space
and into a clearance space as defined by the insertion head proximate an
interface surface of the penetrator such that tension is placed on tissue
along the interface surface to define the tissue drape.

14. A method for providing instruments and instructions for penetrating
soft tissue other than bone in a patient, comprising:providing a surgical
apparatus having a penetrator movable along a penetrator pathway in a
first direction, the surgical apparatus including a capture arm and an
insertion head;providing instructions for operating the surgical
apparatus by:grasping tissue between the capture arm and the insertion
head to form a tissue drape;forming a tissue drape arc along an interior
surface of the capture arm in a second direction generally transverse to
the first direction, the interior surface including an arrangement of a
plurality of gripping members that defines an arcuate gripping radius in
the second direction; andadvancing the penetrator through the tissue
drape arc in the first direction such that the penetrator cuts through
the tissue drape arc at a substantially constant insertion depth relative
to a surface of the penetrator along at least a portion of the penetrator
pathway.

15. The method of claim 14, wherein the surgical apparatus includes at
least one fastener and advancing the penetrator further
comprises:carrying a fastener with the penetrator such that the fastener
can be positioned within the tissue as the substantially constant
insertion depth.

Description:

FIELD OF THE INVENTION

[0001]The present invention relates generally to the field of surgical
instruments such as surgical staplers, clip applicators and sutureless
closure devices. More particularly, the present invention relates to
improvements in tissue manipulation, retention and presentation during
tissue fastening.

BACKGROUND OF THE INVENTION

[0002]When an opening in tissue is created either through an intentional
incision or an accidental wound or laceration, biological healing of the
opening commences through the proximity of the opposed living tissue
surfaces. If the opening is very large or if its location subjects the
wound to continual movement, a physician will seek to forcibly hold the
sides of the opening in close proximity so as to promote the healing
process. Representative methods for forcibly fastening and retaining
tissue during healing has included the use of sutures, clips and staples.

[0003]In the case of skin tissue, for example, healing occurs best when
the opposing dermal layers of the skin tissue are held in proximity with
each other. Human skin tissue is comprised of three distinct layers of
tissue. The epidermal layer, also known as the epidermis, is the
outermost layer and includes non-living tissue cells. The dermal layer,
or dermis, is the middle layer directly below the epidermal layer and
comprises the living tissue of the skin that is the strongest of the
three layers. The subcutaneous, or hypodermis layer is the bottom layer
of skin tissue and includes less connective tissue making this the
weakest layer of skin tissue.

[0004]A recent advance in the area of tissue fastening is the award
winning INSORB® Subcuticular Skin Stapler ("the INSORB® staple")
commercially available from Incisive Surgical, Inc. of Plymouth, Minn.
(www.insorb.com). A number of patent publications address the technology
of the INSORB and include U.S. Pat. No. 6,726,705, as well as in U.S.
Publ. Nos. US2003-0236551 A1, US2004-0059377 A1 and US2004-0059378 A1 to
Peterson et al, all of which are commonly assigned to the assignee of the
present application and all of which are incorporated by reference in
their entirety.

[0005]In a representative embodiment, the INSORB stapler utilizes a
bilateral approach to tissue fastening wherein a fastening apparatus
manipulates opposed sides of tissue to form target tissue zones within
each tissue side wherein a bioabsorbable fastener is subsequently
deployed in a substantially simultaneous bilateral manner to retain
opposed sides of tissue in close approximation so as to facilitate tissue
healing. By maintaining contact of the tissue throughout the healing
process, the healing process is enhanced which results in less chance of
infection, faster recovery and improved aesthetic appearance. In
addition, no subsequent medical follow-up is necessary to remove
fasteners as is typically necessary with non-absorbable fasteners.

[0006]While the tissue fastening advantages of the INSORB stapler have
been recognized as evidenced by numerous design awards and medical
studies, there exists with all varieties of tissue fastening instruments
to further improve on the handling and maintenance of tissue as fasteners
are introduced.

SUMMARY OF THE INVENTION

[0007]The present invention is directed to improvements in the area of
tissue maintenance such as, for example, tissue capture, tissue
presentation and tissue retention, during tissue fastening with a tissue
fastening apparatus. In one representative embodiment, the tissue
fastening apparatus comprises a bilateral subcuticular skin stapler using
bioabsorbable staples, such as the INSORB stapler, although the
improvements disclosed herein apply equally to other tissue fastening
instruments in which tissue maintenance during piercing and placement of
a tissue fastener is important for successful tissue capture.

[0008]In one aspect, the present invention is directed to tissue capture
arms, and more specifically, surface features on said tissue capture arms
that engage captured tissue during capture and retention of the tissue.
In one representative embodiment, the surface features can comprise a
plurality of inwardly projecting "castles" or cubes arranged so as to
maximize traction and tissue control throughout a fastener insertion
process. The inwardly projecting castles and cubes can define an arcuate
profile corresponding to at least a portion of a penetrator radius such
that captured tissue is evenly deformed around at least that portion of
the penetrator, radius, thereby providing for more consistent fastener
placement along an incision. The surface features assist in isolating
captured tissue from external forces such as operator fatigue or
ergonomic issues that can affect consistency along the length of a wound
closure.

[0009]In another aspect, the present invention is directed to tissue
capture arms, and more specifically, improved centering features on said
tissue clamping arms for centering captured tissue and presenting said
tissue to one or more penetrators during a fastener insertion process. In
one representative embodiment, the improved centering features can
comprise a plurality of high and low profile surface projections on an
inner surface of each tissue capture arm arranged to retain and position
captured tissue as the one or more tissue penetrators are deployed into
the captured tissue during fastener deployment. In one embodiment, the
high and low profile surface projections can comprise a castle
arrangement providing omni-directional support during tissue capture and
retention as well as for proving fast tissue decompression upon release
of the captured tissue.

[0010]In another aspect, the present invention is directed to a tissue
capture arm that can capture and temporarily deform tissue to form a
tissue radius that generally, evenly surrounds at least a portion of a
penetrator radius. Through the matching of a tissue contour with a
penetrator contour, a more consistent cut can be made through the tissue,
and consequently a more consistent fastener placement can be accomplished
without regard to differing techniques of medical professionals or tissue
variations commonly found with large incisions such as, for example, an
abdominoplasty. Matching the tissue contour with the penetrator contour
allows tissue to be controlled essentially equally around the penetrator
resulting in increased staple-to-staple consistency along a single
closure.

[0011]In another aspect, a method for reducing user fatigue during closure
of large incisions can by accomplished by providing a fastening
instrument having a tissue capture assembly capable of providing
omni-directional support during capture and retention of the tissue. The
method can further comprise temporarily deforming tissue such that a
tissue radius corresponds to a penetrator radius, thereby providing for
increased staple-to-staple placement consistency along an incision.

[0012]The above summary of the various aspects of the disclosure is not
intended to describe each illustrated embodiment or every implementation
of the invention. The figures in the detailed description that follow
more particularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]These, as well as other objects and advantages of this invention,
will be more completely understood and appreciated by referring to the
following more detailed description of exemplary embodiments of the
invention in conjunction with the accompanying drawings, of which:

[0015]FIG. 2 is a section view of the opening in skin tissue of FIG. 1
taken at line 2-2 of FIG. 1.

[0016]FIG. 3 is a section view of the opening in skin tissue of FIG. 1
arranged in a everted disposition.

[0017]FIG. 4 is a perspective view of a surgical fastening apparatus in a
non-capture disposition according to an embodiment of the present
disclosure.

[0018]FIG. 5 is a bottom view of a tissue interface portion of the
surgical fastening apparatus of FIG. 4 in a capture disposition.

[0019]FIG. 6 is a perspective view of a capture lobe and a penetrator with
the surgical fastening apparatus of FIG. 4 in the capture disposition of
FIG. 5.

[0020]FIG. 7 is a section view of a capture lobe and a penetrator taken at
line 7-7 of FIG. 8.

[0021]FIG. 7a is an end view of a capture lobe according to an embodiment
of the present disclosure.

[0022]FIG. 7b is an end view of a capture lobe according to an embodiment
of the present disclosure.

[0023]FIG. 7c is an end view of a capture lobe according to an embodiment
of the present disclosure.

[0024]FIG. 8 is a bottom view of the tissue interface portion of FIG. 5
including one side of captured tissue.

[0025]FIG. 9 is bottom, partially hidden view of the tissue interface
portion of FIG. 5 including one side of captured tissue.

[0026]FIG. 10 is a section view of a capture lobe and penetrator taken at
line 10-10 of FIG. 9.

[0027]FIG. 10a is section view of the capture lobe and penetrator taken at
an orientation similar to FIG. 10

[0028]FIG. 10b is a section view of a prior art capture lobe and
penetrator taken at an orientation similar to FIG. 10.

[0029]FIG. 11 is a bottom, partially hidden view of the tissue interface
portion of FIG. 5 including one side of pierced tissue.

[0030]FIG. 12 is a bottom, partially hidden view of the tissue interface
portion of FIG. 5 with a surgical fastener place within one side of
tissue.

[0031]While the invention is amenable to various modifications and
alternative forms, specifics thereof have been shown by way of example in
the drawings and will be described in detail. It should be understood,
however, that the intention is not to limit the invention to the
particular embodiments described. On the contrary, the intention is to
cover all modifications, equivalents, and alternatives falling within the
spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE DRAWINGS

[0032]In FIGS. 1 and 2, there is shown a depiction of a typical opening
100 in the surface of skin 102, such as may be made, for example, by a
surgical incision or a wound. Opening 100 defines a first side 104 and a
second side 106 on opposed sides of the opening 100. First side 104 and
second side 106 can comprise a substantially parallel arrangement as
illustrated in FIG. 1, or alternatively, first side 104 and second side
106 comprise substantially non-parallel portions such as commonly
associated with wounds as opposed to surgical incisions. As illustrated
in FIG. 1, for purposes of describing the present invention, opening 100
may be described as having a length or longitudinal orientation parallel
to the y-y axis, a width orientation parallel to the x-x axis, and a
depth orientation parallel to the z-z axis. The x-y-z axis, for purposes
of the present invention, is defined with respect to an external tissue
surface, which in the case of skin 102 is the outer surface. References
to a vertical and horizontal planar orientation in connection with the
present invention are made with respect to the external tissue surface at
the site of the opening in question. As described herein, opening 100 can
have a length from about 8 mm, which can reflect surgical procedures such
as, for example, a mole resection, to about 60 cm, which can reflect
surgical procedures such as, for example, an abdominoplasty.

[0033]As illustrated in FIG. 3, a first vertical inner surface 108
associated with first side 104 and a second vertical inner surface 110
associated with second side 106 can be visualized as meeting along a
generally vertical interface 112. It will be understood that in the case
of an opening that extends over a curved tissue surface, the
corresponding horizontal and vertical surfaces associated with the
opening will be defined with respect to such curved tissue surface.

[0034]It also will be understood that the vertical interface 112 may be
vertical in only one orientation with respect to the tissue surface, such
as in the case when an angled incision has formed the opening 100.

[0035]As illustrated in the sectional view of FIGS. 2 and 3, human skin
102 generally has three discrete layers. These layers comprise an
epidermal layer 114 of mostly non-living tissue having an exterior
surface 116, a dermal layer 118 of mostly living tissue, and a
subcutaneous tissue layer 120. Although embodiments of the present
invention will be described with respect to human skin tissue 102, it
will be understood that the present invention is applicable to creation
of penetration in other types of tissue that are generally considered
soft tissue other than bone, such as fascia, membranes, organs, vessels,
vasculature, vascular pedicles, skin grafts, bladder, muscles, ligaments,
tendons, as well as cartilage, and other biocompatible materials such as
artificial skin, artificial membranes and synthetic mesh.

[0036]It has long been known that the most rapid healing of a skin opening
100 with a minimum of scarring occurs when vertical inner surfaces 108,
110 of the living dermal layer 118 at each side of the vertical interface
112 of skin opening 100 are brought together and held in close contact in
what is referred to as an everted position as is shown in exaggerated
fashion in FIG. 3. To the extent that the primarily non-living material
of epidermal layer 114 can be excluded from the healing opening, the
rapidity and level of scar tissue formed during the healing process will
be minimized. One manner by which the epidermal layer 114 can be excluded
from the healing opening is precisely control tissue capture and
presentation prior to and during insertion of a surgical faster.

[0037]A representative surgical fastening apparatus 200 incorporating
features of the present invention for precisely controlling tissue
capture and presentation is illustrated generally in FIG. 4. Surgical
fastening apparatus 200 can generally comprise a body 202 and a tissue
interface portion 204. As depicted, body 202 may resemble the physical
appearance of the aforementioned INSORB stapler although the tissue
manipulation features of the various embodiments of the present invention
are equally applicable to a variety of alternative body configurations
including for example, traditional skin and laparoscopic stapling
devices.

[0038]Tissue interface portion 204 is more clearly illustrated in FIG. 5.
Tissue interface portion 204 can include a first capture arm 206, an
insertion head 208 and a second capture arm 210. As depicted, first
capture arm 206 and second capture arm 210 can be simultaneously,
proximally located on opposed sides to the insertion head 208 though it
is to be understood that variations on the surgical fastening apparatus
200 and fasteners could allow for and/or require sequential approximation
of the first capture arm 206 and the second capture arm 210. Furthermore,
the concepts related to tissue capture and positioning during insertion
of a fastener can apply equally to instruments utilizing only a single
capture arm, a single penetrator, a single curved penetrator and
combinations thereof.

[0039]Referring to FIG. 5, first capture arm 206 and second capture arm
210 can be configured in a mirror image relation generally comprising an
arm body 212 having a grasping surface 214, an exterior surface 216, a
top surface 218 and a bottom surface 220. Grasping surface 214 can
comprise a distal tip 222, a recessed surface 224 and a capture lobe 226.
Distal tip 222 can comprise a distal grabbing member 228 while capture
lobe 226 comprises a plurality of proximal gripping members 230. Distal
gripping member 228 and proximal gripping members 230 may comprise either
similar or dissimilar physical configurations.

[0040]Referring again to FIGS. 4 and 5, insertion head 208 can comprise a
top head surface 242, a first side interface surface 244, a second side
interface surface 246, an end surface 248, a penetrator bore 24, a bottom
head surface 250 and a body interface portion 251. Both first side
interface surface 244 and second side interface surface 246 can include a
concave positioning guide 252.

[0041]As illustrated in FIG. 5, surgical fastening apparatus 200 can
comprise a penetrator assembly 254 located proximate the tissue interface
portion 204. The penetrator assembly 254 can comprise a pair of
penetrators 256a, 256b operably connected with a penetrator body member
258. While illustrated as having two penetrators 256a, 256b, it will be
understood that the principles of tissue capture, maintenance and
fastening are equally applicable to the use of a single penetrator. As
illustrated in FIG. 7, penetrator assembly 254 can be utilized to carry
and deposit a surgical fastener 260 as will be further described below.

[0042]Surgical fastener 260 can comprise suitable materials of
construction such as, for example, biologically compatible metals such as
stainless steel or nitinol or biologically compatible plastics. In one
embodiment, surgical fastener 260 can comprise a bioabsorbable fastener
as described in U.S. Pat. No. 7,112,214, which is herein incorporated by
reference in its entirety. It will be recognized that in alternate
embodiments, a surgical apparatus in accordance with the present
invention may be utilized for creating controlled penetrations of tissue
for a variety of surgical purposes, including insertion of fasteners,
such as for wound closure, tissue anchoring, stabilization, or repair, as
well as attachment or anchoring of medical devices, such as slings, mesh,
or implantable apparatus, or medical implants, such as ligaments,
tendons, muscles, or organs.

[0043]Capture lobe 226 is more clearly illustrated in FIG. 6. Capture lobe
226 generally comprises a continuous lobe surface 262 defined by a lobe
leading surface 264, a lobe interface surface 266 and a lobe trailing
surface 268. In one representative embodiment, continuous lobe surface
262 has a generally convex appearance. Proximal gripping members 230 are
arranged in both a first direction and a second direction along the
continuous lobe surface 262, wherein the first direction is generally
parallel to and along a penetrator travel path 269 while a second
direction is generally transverse to the first direction Proximal
gripping members 230 define a capture surface 272 having a plurality of
raised edges 273 and a plurality of channels 274. Raised edges 273
present gripping edges for gripping tissue while channels 274 proved
spaces into which tissue can be compressed and/or squeezed. Raised edges
273 and channels 274 can be arranged in a variety of orientations, for
example, along the first direction, the second direction and combinations
thereof. Capture surface 272 can be presented using a variety of
configurations for proximal gripping members 230 including, for example,
a raised castle configuration 275 or a raised cube 276. Raised castle
configuration 275 can comprise a projecting body 277 in which, capture
surface 272 is generally defined by a plurality of projecting corner
cubes 278 extending upward from a surface 279 of the projecting body 277.
Either alternatively or in conjunction with raised castle configuration
275, a plurality of raised cubes 276 can be arranged along the continuous
lobe surface 262, and more specifically the lobe interface surface 266 so
as to define the capture surface 272. While gripping members 230 are
described and illustrated as comprising cube or castle configurations, it
will be understood that a variety of geometrical configurations can be
utilized to present raised edges and channels including, for example,
cylinders, pyramids, crosses and the like. In addition, surface 279 on a
projecting body for any suitable geometric configuration of gripping
member 230 can comprise a concave or scallop-shaped surface.

[0044]Proximal gripping members 230 are arranged in the second direction
in a staggered configuration 282 as illustrated in FIG. 7 such that
tissue can be captured, retained and positioned at varying distances from
the continuous lobe surface 262 so as to define an arcuate gripping
radius 284 illustrated at arc a-a in FIG. 7 wherein at least a portion of
arcuate gripping radius 284 corresponds to a penetrator piercing arc 286.
As will be illustrated and described below, the similarity between
arcuate gripping arc 284 and penetrator piercing arc 286 allows for
piercing of tissue and corresponding placement of surgical fastener 260
at a fixed placement distance or depth 288 within the dermal layer 118 as
measured from the exterior surface 118 of epidermal layer 114 as
illustrated in FIGS. 9 and 10. Proximal gripping members 230 can be
arranged along continuous lobe surface 262 in any of a variety of
suitable configurations for defining arcuate grip radius 284 as
illustrated in FIGS. 7a, 7b and 7c.

[0045]Use of surgical fastening apparatus 200 and the advantages of the
tissue capture and maintenance components described above is illustrated
in FIGS. 8, 9, 10, 11 and 12. For purposes of clarity and to better
describe the use of surgical fastening apparatus 200, many of the
drawings are illustrated from a bottom viewing orientation in which
second side 106 is illustrated being pierced and captured while first
side 104 is not depicted so as to more clearly illustrate the
interactions occurring at tissue interface portion 204. It will be
understood that in certain representative embodiments, first side 104 and
second side 106 can be either simultaneously or sequentially captured at
tissue interface portion 204.

[0046]As illustrated in FIGS. 9 and 10, a first tissue capture step is
illustrated in which surgical fastening apparatus 200, and more
specifically, tissue interface portion 204 has captured second side 106
between grasping surface 214 on second capture arm 210 and insertion head
208 using the actuation mechanisms and procedures described in U.S.
Patent Publication 20040059377, which is herein incorporated by reference
in its entirety. As seen in FIG. 8, a clearance space 290 between lobe
interface surface 266 and concave positioning guide 252 is generally
increased in comparison to a leading clearance space 292 between the
concave positioning guide 252 and the lobe leading surface 264 and a
trailing clearance space 294 between the concave positioning guide 252
and the lobe trailing surface 268. Due to the viscoelastic nature of skin
102, and most especially dermal layer 118 and subcutaneous tissue layer
120, clearance space 290 allows increased amounts of tissue to be
squeezed out of leading clearance space 292 and trailing clearance space
294. This squeezing action at leading clearance space 292 and trailing
clearance space 294 creates tension along the length of the skin 102
captured in clearance space 290 such that a tissue drape 296 is formed
along the lobe interface surface 264 that substantially assumes a tissue
drape arc 298 substantially resembling arcuate gripping radius 284 as
illustrated in FIG. 7.

[0047]As tissue drape 296 is formed along lobe interface surface 266, the
epidermal layer 114 is stretched across and squeezed into the proximal
gripping members 230. Regardless of how capture surface 272 is defined,
for example with raised castle configuration 275 or raised cube 276 and
combinations thereof, the combination of raised edges 273 and channels
274 of capture surface 272 grips the epidermal layer 114 and provides
traction that prevents the epidermal layer 114 from sliding along the
lobe interface surface 266 as well as maintaining the arcuate nature of
tissue drape arc 298. The combination of raised edges 273 and channels
274 provides omni-directional support on tissue that is captured and
squeezed against the proximal gripping members so as to avoid slippage of
the captured tissue along either the first direction, the second
direction or combinations of directions relative to the lobe interface
surface 266. Proximal gripping members 230 can be especially beneficial
in gripping epidermal layer 114 in instances when the epidermal layer is
wet and/or lubricated with anesthetics, lotions or other topicals. In
addition, the tractive features provided by proximal gripping members 230
can serve to isolate the captured tissue from external user based forces
such as operator fatigue or ergonomic issues that could negatively impact
the tissue capture and subsequent tissue fastening.

[0048]As penetrator 256b is advanced into and through the tissue within
clearance space 290, dermal layer 118 and subcutaneous tissue layer 120
essentially piles up against the penetrator bore 249 as illustrated in
FIG. 11, while the proximal gripping members 230 maintain the position of
epidermal layer 114 and counteract the force of penetration. As the
penetrator 256b approaches penetrator bore 249, penetrator 256b pierces
the dermal layer 118 of tissue drape 296. As the penetrator 256b pierces
the dermal layer 118, the tissue drape arc 298 insures that penetrator
256b does not pierce or button-hole the epidermal layer 114 by
maintaining an essentially constant insertion depth 300 shown in FIG. 10
measured from exterior surface 116 of skin 102. Generally, constant
insertion depth 300 is within a range of about 0.005'' to about 0.021'',
and is most preferably about 0.013'', such that penetrator 256b is always
piercing within the dermal layer 118. As constant insertion depth 300 is
physically defined by the interaction between the penetrator 256b and the
lobe interface surface 266/proximal gripping members 230, the constant
insertion depth 230 can be maintained regardless of differing user
techniques, operator fatigue or tissue variability that is often
encountered during closure of large incisions. As penetrator 256b enters
the penetrator bore 249, the tissue piled up against the penetrator bore
249 is pulled over a retention member illustrated as cleat 304 on the
surgical fastener 260 such that surgical fastener 260 resides in the hole
cut by penetrator 256b in dermal layer 118.

[0049]The principles for consistently defining constant insertion depth
300 are further illustrated in FIGS. 10a and 10b. Referring to FIG. 10a,
proximal gripping members 230 along lobe interface surface 266 grip the
epidermal layer 114 to define the tissue drape arc 298. The tissue drape
arc 298 has a generally constant radius R1 centered upon a penetrator
center point 302. Likewise, the penetrator piercing arc 286 has a
generally constant radius R2 centered upon the penetrator center point
302. Tissue drape arc 298 remains generally constant between an uppermost
proximal gripping members 304 and lowermost proximal gripping members 305
such that R1 is constant for an arc length 306 of about 60° to
about 120°, and most preferably greater than about 90°.

[0050]Referring to FIG. 10b, a prior art lobe interface surface 310 is
illustrated that lacks proximal gripping members 230, and thus has no
mechanism for defining tissue drape arc 298. While, the penetrator
piercing arc 286 has continues to have generally constant radius R2
centered upon the penetrator center point 302, radius R1 is no longer
constant such that a variable insertion depth 312 is depicted.

[0051]One advantage of the physical definition of constant insertion depth
300 provided by the present disclosure is that it allows for two medical
professionals to work from opposite ends of large incisions so as to
reduce overall closure time, while providing consistent placement of
surgical fastener 260 regardless of operator technique or fatigue. This
can be especially valuable in especially large closure situations such
as, for example, an abdominoplasty procedure.

[0052]Once penetrator 256b has carried the surgical fastener 260 into the
penetrator bore 249, the penetrator assembly 254 can be withdrawn as
illustrate in FIG. 12 such that penetrator 256b backs out of the hole
pierced in dermal layer 118. As penetrator assembly 254 is withdrawn, the
tissue pulled over cleat 304 prevents the surgical fastener 260 from
being withdrawn. As penetrator assembly 254 is fully withdrawn, second
capture arm 210 can be withdrawn from insertion head 208 thereby
releasing the captured tissue and allowing for tissue interface portion
204 to be removed or repositioned for subsequent tissue capture and
fastener placement along the length of opening 100.

[0053]While representative embodiments of the invention have been
described with respect to fastening of skin, and more particularly,
dermal tissue, it will be recognized that the invention is also
applicable to other types of tissue such as facia, muscle, ligaments,
cartilage, tendons and the like.

[0054]Although the invention has been described with respect to a variety
of representative embodiments, it will be understood that numerous
insubstantial changes in configuration, arrangement or appearance of the
elements of the present invention can be made without departing from the
intended scope of the invention. Accordingly, it is intended that the
scope of the invention be determined by the claims as set forth.